Formwork for erecting concrete structures



May 24, 1966 l J. BssNER 3,252,199

FORMWORK FOR ERECTING CONCRETE STRUCTURES Filed Mayvlv, 1962 1o sheets-sheet 1 Pfg. f

l' l i May 24, 1966 J. BssNER v FORMWORK FOR ERECTING CONCRETE!v STRUCTURES lO Sheets-Sheet 2 Filed May 17, 1962 J. BSSNER FORMWORK FOR ERECTING CONCRETE STRUCTURES May 24, 1966` l0 Sheets-Sheet 5 Filed May 17, 1962 May 24 1966 l J. BssNER 3,252,199

FORMWORK FOR ERECTING CONCRETE STRUCTURES Filed May 17, 1962 10 Sheets-Sheet 4 Pfg. 4

` May 24, 1966 .1. BSSNER FORMWORK FOR ERECTING CONCRETE STRUCTURES 10 Sheets-Sheet 5 Filed May 17, 1962 May 24, 1966 J. BSSNER v 3,252,199

FORMWORK FOR ERECTING CONCRETE STRUCTURES Filed May 17, 1962 10 Sheets-Sheet 6 May 24, 1966 J. BSSNER FORMWORK FOR ERECTING CONCRETE STRUCTURES Filed May 17, 1962 10 Sheets-Sheet 7 May 24, 1966 J. BSSNER FORMWORK FOR ERECTING CONCRETE STRUCTURES lO Sheets-Sheet 8 Filed May 17, 1962 May 24, 1966 JgBSsNER 3,252,199

FORMWORK E 'OR ERECTING CONCRETE STRUCTURES Filed May 17, 1962 l0 Sheecs--SheerI 9 May 24, 1966 J. BSSNER FORMWORK FOR ERECTING CONCRETE STRUCTURES Filed May 17, 1962 10 Sheets-Sheet lO Fig. .9b

s anims. (ci. 25u-rs1) This invention relates to a formwork for erecting towerlike structures of concrete, of any desired longitudinal and transverse sectional profiles, which tormwork comprises a vertically extending central pole anchored on the completed part of the structure, and inner and outer formwork skins, both of which have a variable peripheral extent.

Such a for-mwork is known, which comprises a central pole, from which a carrying ring structure radially displa-ceably carrying the outer formwork skin is suspended by means of a jib arm and ropes.

ln the known formwork, the inner formwork skin is not suspended from the carrying ring structure but is carried by a working platform provided on the com pleted part of the struct-ure.

Where the k-nown iormwork isused, the operation of placing the concrete is performed by lirst moving the outer formwork by lifting tackles to the height section where the concrete is to be placed, whereafter the construction ot` the inner tformwork skin is continued from the working platform, followed by placing the concrete.

Whereas the outer -fonmwork skin is advantageously suspended in the known ormwork so as to be vertically adjustable and radially displaceable, the inner formwork must be constructed piecemeal in the orthodox manner by the workers standing on the working platform; this is very troublesome and time-consuming.

To avoid the disadvantages of the known formwork for tower structures, the formwork of the type mentioned above is so constructed according to the invention Ithat the central pole is surrounded by a slider which is vertically slidable on the pole and lfrom Which at least the inner lfor-mwork skin is suspended by suitable means so as to lbe radially displaceable and tiltable relative to the tower axis.

The outer tormwork skin may be vertically adjnstably suspended in .a manner known per se from jib `arms radially extending from the central pole and may be connected by spacers to the inner formwork skin.

yIn a particularly suitable embodiment, the formwork according to the invention comprises radially extending rails which are secured to the top end of the slider and from which the inner tormwork skin and the outer vformwork skin .are suspended by suitable means so as to be radially displaceable and tiltable.

In the formwork according to the invention, the formwork skins may consist of overlapping sheet metal niembers. Alternatively, the formwork skins may be formed by the web portions of vertically extending' channels, which are contiguous at their flanges, and the skins may consist of individual sections, the wedge-shaped or triangular gaps between the individual sections being spanned by a stressable cover plate.

If the tformwork skins of the `forrnwork yaccording to the invention are composed of channels lying one beside States Patent O 3,Z5Z,l99 Patented May 24, 1965 A(IC the other, with cover plates provided between the individual formwork skin sections, a preferred embodiment comprises adjustable power transmitting members which span the gaps in the outer formwork skin and in the inner formwork skin in such a manner that the annular tensile stress set up in the outer formwork skin and the yannular compressive stress set up in the inner for-mwork skin when the concrete is being lled in are transmitted by these members from one r.formwork skin section to' the next.

'Ihe method of erecting towerlike structures of concrete, of any desired longitudinal and transverse sectional profile, with the -formwork according to the invention is characterized in that the inner and outer formwork skins are Ifirst pulled upwardly by a distance substan-tially ture, followed by releasing the central pole land pulling it upwardly along the slider to s-uch an extent that the lower end of the central pole engages the lower edge of the forrnwork skins, wherealfter the central pole is again secured to the concrete which has set, the ormwork skins are released and pulled upwardly in height sections etc.

'Ihe advantages and details of the invention will become apparent `from the following description of illustrative embodiments shown in the accompanying drawings, in which:

FIG. 1 is a vertical sectional view taken through lthe center line of a -rst embodiment of the formwork according to the invention, which is applied to a partly completed towerlike structure.

FIG. 2 is a sectional view ,taken on line lI-ll in FIG. l, with the jib arms at the top end of the central pole being shown in dash lines.

FIG. 3 is a vertical sectional View similar to FIG. l and shows a second embodiment of the iformwork according to the invention.

FIG. 4 is a view taken partly in vertical section on line IV-IV of FIG. 5, similar to FIGS. 1 and 3, and shows another embodiment of the formwork according to the invention, the slider being shown on the left of the figure on another level than on the right.

FIG. 4a is an enlarged view partly in vertical section on line lVa-lVa of FIG. 2.

FIG. 5 is a view partly in transverse section taken at right angles to the center line of the tower along the line V-V of FG. 8 and shows the embodiment of the formwork illustrated in FIG. 4.

FIG. 6 is an enlarged View showing a portion of FIG. 5 (circle 3).

FIG. 6a is a sectional View taken on line Vla-Vla in FIG. 6.

FIG. 7 is an enlarged View showing another portion of FIG. 5 (circle 4).

FIG. 7a is a sectional view taken on line VIIa-VIIa in FIG. 7.

FIG. 8 is an elevation taken in the direction of the arrow 3 A in FIG. 4 and showing the formwork skins, the outer formwork skin being disposed in the upper third and the inner formwork skin in the middle third.

FIGS. 9a, b, c and d are a diagrammatical illustration of the method according to the invention.

According to FIG. 1, a central pole 111 is releasably secured to the top end of a previously partly completed structure 114 by radially extending carrying arms 112. The central pole 111 may be a tube or, as shown in FIG. 4, 'consist of steel tubes Welded together. Ra-dially extending jib arms 119,' which are indicated with dash and dot lines in FIG. 2, are secured to the top end of the central pole 111. An outer for-mwork skin 130 is vertically adjustably suspended from these jib .alms in known manner by means of ropes, which can be wound on a Winch 138. Working platforms 136, 137 and usual protective devices may be provided on the outer formwork skin.

The crux of the invention is constituted by a slider 115, which surrounds the central pole 111 and just as the central pole 111 may consist of a tube or of steel tubes welded together. The slider 115 is secured to the central pole 111 so that the slider 115 is vertically displaceable relative to the central pole 111. For this purpose, the slider 115 may be provided, e.g., with rollers 116, which run on rails suitably arranged on the central pole 111. It

is obvious that any other sliding connection between the slider and the central pole maybe provided.

An inner formwork skin 131 is suspended by radially adjustable means from the slider. The length-adjustable members consist, e.g., of radially extending screws 1 27 and diagonally extending stiffening screws 120. The screws are articulated at one end to the slider and at the other end to a skeleton structure 129, 132 serving to stiifen the inner formwork skin 131. 4

The skeleton for stiiening the inner formwork skin 131 consists of substantially vertical posts 132 and annular channels 129. An outer formwork'skin 130 may be similarly stiiened by vertical posts 133 and annular channels 134.

It is obvious that the curved annular channels must be re-bent and shortened at each new height section inwhich concrete is to be placed.

A Working platform 135 is provided at the t-op end of the slider. -It is obvious that Working platforms may be provided at other points as may be required.

The placing of the concrete for the tower with the aid of the described formwork is performed as follows:

When the central pole 111 has been secured with carrying arms 112 to the top end of the previously completed part 114 of the structure, the Winches 138 are operated to pull the outer formwork skin 130 upwardly into the next height section in which concrete is to be placed. The outer lformwork skin is then adjusted to the dimensions of the tower which are desired in this height section. Before the inner formwork skin is caused to follow up, the iron reinforcements are introduced from the inside into the space to be yfilled with concrete.

Then the slider 115, from which the inner formwork skin 131 is suspended Iby means of the screws 120, 127, is pulled upwardly by means of winches 117 and ropes 118 along the central pole 111 until the skin 131 is aligned with the outer formwork skin 130 and is thus disposed in the height section in which concrete is to be placed. The inner forrnwork skin 131 is adjusted to the changed dimensions of the tower by actuation of the screws 120, l127 and by a change in the peripheral extent and replacement of the channels 129.

It is apparent that the forrnwork skins in the form- Work according to the invention cannot only be adjusted in a radial direction but may also Ibe tilted relative to the center line 110 of thetower. This may be accomplished iby a simultaneous actuation of the screws 127. Hence,

the formwork according to the invention is not only suitable for making towers having a straight generatrix (cylinder, cone) but also for making towers having a curved generatrix, e.g., in the form of a parabola. The vertical Section of the formwork skins may nevertheless be a straight line in general because the curvature of the generatrix of the tower will be very small in most cases. Strictly speaking, the generatrix will not be a continuously .curved line but a repeatedly broken line in these cases.

For towers having a highly curved generatrix it is possible, of course, to use formwork skins which are curved in the vertical direction.

When the outer and inner formwork skins have been aligned and connected to each other by spacers 128, the liquid concrete` may be filled in after it has been lifted by a lift or elevator in the interior of the tower. When the concrete has set, the formwork skins remain temporarily in position. The carrying arms 112 of the central pole 111 are detached from the wall 114 of the structure. Then the central pole 111 is pulled upwardly by means of winches 117e and ropes 11-8a along the slider 115 anchored in the Wall 114 of the structure yuntil the carrying arms 112 are closely below the `forrnwork skins 130, 131. Then the carrying arms 112 are againsecured to the wall 114 of the structure, the formwork skins are detached and pulled upwardly in the manner described hereinbefore to the next height section in which concrete is to be placed. v

Whereas this climbing operation of a forrnwork is known per se, it enables a very fast `and economical erection of towerlike structures in conjunction with the formwork according to the invention.

It is suitable to construct below and up to the central pole 111 a frame structure 140, which serves for accommodating a lift and stairs or ladders for the workers.

FIG. 3 is a vertical sectional view showing another embodiment of the formwork according to the invention. In this embodiment, two formwork skins 230, 231 are suspended from a slider 21.5 by means of slide rails 222. The suitably stiffened rail 222 is secured to the top end of the slider and extends radially. The two formwork skins 230, 231 are radially displaceably suspended from the rail 222 by means of rollers 223, 224. The inner formwork skin is again radially supported by screws 227, which are articulated at one end to the slider 215 and at the other end to substantially vertical posts 232. The outer formwork skin is adjusted by means of spacers 228. The formwork skins 230, 231 are again stiiened by vertical posts 233, 232 and 234, 229. As in the example shown in FIGS. 1 and 2, a central pole 211 is detachably secured by means of carrying arms 212 to the previously completed part 214 of the structure. In this embodiment, jib arms 219 extending to all sides from the center line 210 of the tower are provided at the top end of the central pole 211. These arms may preferably carry a roof 236 protecting the structure being erected from the weather.

Frame structures 225 may be provided, if desired, which vertically depend from the outer ends of radial jib arms 219 and are secured by suitable means 226 to the vwall 214 of the structure being erected. The frame 225 may carry working'platforms or vertical rails, which may serve as tracks for rollers 237 at the outer ends of the slide rails 222. This will further improve the guidance of the slider 215. The method of erecting towerlike structures with the embodiment of the formwork according to the invention shown in FIG. 3 is similar to the method performed with the forrnwork shown in FIG. 1. However, the inner formwork skin 231 and the outer formwork skin 230 are jointly pulled upwardly. The slider isv pulled up along the central pole 211 by means of Winches 217 and ropes 218 and the lifting of the central pole 211 along the fixed slider 215 is effected by Winches 217g, on which ropes 218e are wound up.

Whereas it has been assumed that the tower has a circular cross-section in connection with the two embodiments described hereinbefore and with those to be decase, the radially extending parts and the form of the formwork skins will have vto -be selected accordingly whereas the basic structure of the formwork according to the invention andthe method will not be changed.

In the third embodiment of the formwork according to theinvention, `shown in FIGS. 4 to 9, the entire formwork has hexadic symmetry. In the vertical sectional view shown in FIG. 4, a showing only on one side of the axis of symmetry would be sufficient. To illustrate the method to be described hereinafter of erecting a tower with a formwork according to this embodiment, two different phases of the method are shown on the left and right of the tower axis 10.

A central pole 11 of the formwork is anchored to the previously completed part 14 of the tower by spreader arms 12, sleeves 13 welded to these arms, bolts 13a and spacers 28 embedded in the concrete. The arms 12 can be locked in position by levers 12a. A vertically slidable slider 15 surrounds the central pole 11. Rollers 16 connect the central pole 11 to the slider 15 and radially locate the latter.

The slider 15 is provided at its top end with jib arms 22, which are at right angles to the center line 1t) of the tower and extend radially outwardly. The embodiment described comprises twelve of such jib arms, which are regularly angularly spaced (FIG. 5).

The jib arms 22 are stiftened by a grid structure 21 and formed as rails on their underside.

Below each jib arm 22, the slider 15 is provided with two spreader arms 27, 27a, which extend parallel to the respective jib arm and have a predetermined spacing with respect to the jib arm and to each other.

The slider 15 is suspended from ropes 18, which are secured at one end to jib arms 19 carried by the central pole and at the other end to a winch 17 carried by the slider. The slider may be additionally connected to the jib arms 19 by means of ropes, holding rods or the like 18b.

Whereas the winches 17 serve to pull the slider 15 upwardly along the central pole 11, further winches 17a are provided with which the pole can be pulled upwardly relative to the slider anchored on the previously completed part of the towerlike structure, when theanchoring means (13a, 12a) of the pole have been released. As is shown in FIG. 4, the two Winches 17, 17 form suitably a unit.

Each of the raillike jib arms 22 carries three radially displaceable rollers 23', 24' and 25', which can be iixed in position by suitable means and from which substantially vertically depending carrying rods 23, 24 and 25 are suspended.

CII

The innermost carrying-rod 23 is articulated at two points to portions 27a of the two spreader arms so that this rod 23 can be adjusted to and lixed at a desired distance from and angle to the tower axis.

The two outer carrying rods 24, 25, which are radially displaceable and can be xed in position, are connected by connecting tubes 26 to form a rigid frame. As con trasted with the `carrying rod 23, the two carrying rods 24, 25 are not directly connected to the associated rollers 24', 25'. Between each roller 24 and 2S and the associated carrying rod 24 or 25, a screwed or telescopic connection 24 or 25 is provided so that the distance between the roller and the associated carrying rod can be decreased or increased. Operation of the two screwed or telescopic connections in mutually opposite senses will enable an adjustment of the iixed frame formed by the carrying rods 24, 25 and the connecting tubes 26 to a desired angle with respect to the tower axis, and the xation of the frame at this angle, just as has been described for the carrying rods 23.

By means which will be described hereinafter, the inner formwork skin is suspended from the inner carrying rods 23 and the outer formwork skin is suspended from the frame 24, 25, 26. By an adjustment of the rods 23, 24, 25, the two formwork skins may be -adjusted in each height section in which concrete is to be placed to the desired tower diameter, the desired wall thickness of the tower and the desired taper of the tower. When the carrying rods 23 and the frame 24, 25, 26 have been adjusted, they are firmly screw-connected by means of bolts 29 to the spacers 28 between the two formwork skins 30, 31 so that the formwork skins are held in position by an extremely rigid and strong structure. Whereas the bolts 29 of the outer formwork skin 30 extend through the tubes 26, the bolts 29 of the inner formwork skin 31 extend through sleeves 27h articulated to the spreader arms 27a.

With reference to FIGS. 5 to '8, the structure of the formwork skin and its fixation to the previously described structure will be explained hereinafter.

According to FIGS. 5 to 8, an inner formwork skin 31 and an outer formwork skin 3d are provided, which consist in known manner of substantially vertical channels 34, a certain number of which, e.g., thirty-nine in the outer formwork skin 30 and thirty-three in the inner formwork skin 31, are firmly contiguous with each other at their narrow sides and are screwed or welded together to form formwork skin sections.

In the'embodiment shown in FIG. 5, each of these sections extends over an angle of 60 so that the outer and inner formwork skins are composed of six of such sections each. The angular extent of each section wi-ll obviously depend on the dimensions of the structure to be erected and the value of 60 has been selected only as an example.

The central channel (the twentieth in the sections of the outer formwork skin and the seventeenth in the sections of the inner formwork skin as shown in FIG. 5) has a larger width than the other channels 34, preferably twice the width thereof. This central channel 34a or 3411 shown particularly in FIG. 7 i-s suitably not screw-connected but welded to the adjacent narrower channels 34.

According to FIGS. 5 and 7, the anges of the central channel 34a of each section of the outer formwork skin 30 extend over vertical guide rails 44, which consist preferably of a plate formed into a hollow T. The rails are not xed but have a certain freedom of movement behind the flanges of the channel 34a to permit of a slight curvature of the formwork skin surface corresponding to the curvature of the tower. A web portion 44a of the hollow T is welded throughout its length to the carrying rod 24. Hence, the position of the inner formwork skin 31 is determined bythe adjustment of the frame 24, 25, 26. The guide devices are generally indicated at 36 in the drawing.

In each section of the inner formwork skin 31, rails 44 consisting of sheet metal formed into a hollow T are provided on the central channel 34h and have a web portion 44a which is welded throughout its length to the carrying rod 23. Hence, the position of the inner formwork skin 31 is determined by the adjustment of the carrying rod 23. The guide devices for the inner formwork skin are generally indicated at 36.

A vertical displacement of the formwork skin is prevented by bolts 29, which extend through connecting rods 26, sleeves 27a articulated to the spreader larms and holes in the central channels 34a and 34h and in the formwork skins 30 and 31 into screw-threaded spacers 2S. The spacers 28 are provided with anchoring parts 28a because they are to remain in the concrete when the' structure has been completed and serve for the iixation, e.g of antennas or other means to the tower.

Hence, the bolts 29 perform a threefold function: They connect the frame 24, 25, 26 to the carrying rod 23, hold the spacer 28 in position and locate the formwork skins in the vertical direction.

The formwork skins 30, 31 are connected tby ropes to Winches 33 and 32, respectively, shown in FIG. 4, and can thus be pulled upwardly when the bolts 29 have been removed.

The above-described subdivision of the annular formwork skins into individual sections enables an adjustment to the tower dimensions, c g., to the peripheral extent, wall thickness and taper of the tower, which change as the height increases. In general, the peripheral extent and theinclination relative to the axis 10 must be-reduced and the curvature of the formwork skins must be increased as the height increases'. 4

Whereas the curvature of the formwork skins can be vreadily varied within wide li-mits if the thickness of the rails 44, 44. The plates 41 have a bracket 41a or 41a l welded to them, the width of which is exactly equal to the length of the flanges of the channels 34. The brackets 41a, 41a' are rmly welded to the vcarrying rods 24 and 23, respectively, at regularly spaced points 50, 50 by welded tubes 35a and 35a'. The tubes 35a, 35a form preferably extensions of the tubes 26 and of the sleeves 27b, re-

spectively.

Tightening devices 35, 35' according to the invention for transmitting the annular tensile stress set up in the outer formwork skin 30 and the annular compressive stress set up in the inner formwork skin 31 during the filling of the concrete between the formwork skins are provided between adjacent formwork skin sections at a plurality of points spaced .along the brackets 41a, 41a (FIGS. 4a and 8). The annular tensile and compressive stresses are set up because the concrete introduced between the forrnwork skins tends to urge the outer formwork skin outwardly and the inner formwork skin inwardly.

The devices 35, 35 consist of a ring tightening rail 38 or 38', which bears on the flanges of the channels of two adjacent formwork skin sections and on which two clamping riders 37 or 37' are tangentially displaceable, which can be locked in position by levers 39, 39.

The two clamping riders 37 on an outer ring tightening rail 38 have offset ends 40 facing each other and extendin-g behind the channel flanges disposed at the end of each forrnwork skin section.

In the inner formwork skin 31, the clamping riders 37 are provided in an inverted arrangement. The offset ends 40 of the clamping riders 37' are oppositely directed and extend behind those ends of the two channels at the end of two formwork skin section-s which are remote from the gap 34C. i

The ring tightening rails are preferably slightly curved in accordance with the mean curvature of the tower.

Wing screws 42, 42 extend through holes in the ring tightening rails 38, 38', in the brackets 41a, 41a and in the cover plates 41 into screw-threaded openings in a spacer 28. Tightening the wing screws 42, 42 will perfectly align the two sections of theformwork skin 30 or 31, the cover plates 41, 41 and the ring tightening rails 38, 38'. The brackets 41a, 41a will then firmly bear on the ring tightening rails 38, 38.

The adjustment of the carrying frames (23, 24, 25, 26) at the position of the tightening devices 35, 35 and at the positions 50, 50 is effected as described hereinbefore in connection with the positionsof the sliding guide devices 36, 36'.

Being adjustable, the tightening devices 35, 35 can take up the annular tensile and compressive stresses set up when the concrete is being lled on any level so that the need for the stiffening members previously required is eliminated and the formwork skins are virtually self-supporting.

The tightening devices 35, 35 and the guide devices 36, 36 are arranged in alternation with a certain angular spacing on the periphery of the towerlike structure to be erected. In the embodiment shown in FIG. 5, the angular spacing between the tightening devices 35, 35' and the sliding guide devices 36, 36 is 30 whereas the spacing of two successive similar devices is 60. As a result, the embodiment described comprises six tightening devices and six guide devices. The number of the tightening and guiding devices provided on the periphery of a climbing formwork according to the invention will obviously depend entirely on the diameter and peripheral extent of the towerlike structure to be erected.

When the erection of the tower has proceeded to a stage in which the gaps 34e are approximately equal to the length of the brackets 41a, 41a', one or more of the screw-connected channels are removed to increase the gaps 34C to a desired size, whereafter they will again be progressively decreased.

When the bolts 29 and the locking levers 39, 39 have been released and pulled out, the formwork skin described will automatically adjust itself to the wall thickness, peripheral extent and conicity of the structure to be erected while the formwork skin is being pulled upwardly; these dimensions are determined by the carrying frames 23, 24, 25, 26. As has been mentioned, itis not necessary to rebend or cut off any parts but it is suicient to release and resecure bolts and screws.

According to FIG. 6, the carrying rods 23, 24 on the level of the tightening devices 35, 35 may be somewhat more widely spaced from the formwork skins to leave room for the wing screws 42.

A particularly suitable method of manufacturing a towerlike structure with the vabove-described climbing formwork according to the invention is perfonmed as follows:

The tower is constructed by placing concrete in height sections according to FIGS. 4 and 9a to d. A height section which corresponds approximately to the height of the formwork skin will be called a height subsection.

That section in which concrete can be placed without pulling the slider 15 will be referred to as a height subsection group. In the present embodiment it consists of two subsections but may be composed of three and more subsections depending on the prevailing conditions.

The method according -to the invention is commenced by anchoring the central pole Ain the foundation or in a previously completed subsection I. 'Ihe slider 15 is in its lowerrnost position, shown on the left in FIG. 4 and in FIG. 9a.

Now the carrying frames 24, 25, 26 and the carrying rod 23 are adjusted to the desired wall thickness, the desired peripheral extent and the desired taper of the structure in Vthe respective height as has been described hereinbefore. This adjustment is locked by'the locking means 22a and by clips 27e and the spreader arms 27. The outer one of the formwork skins still disposed in the subsection I is now pulled upwardly by operation of t-h-e winches 33 when the corresponding bolts 29 have been removed and the clamping riders 37 Ihave been released by actuation of the levers 39 (FIG. 6).

The slide rails 44, 44 and the cover plates 41 have a height corresponding to.the length of about three subsections. By the frames 23, 24, 25, 26 they are -exactly aligned so that the upwardly sliding formworkskin is exactly guided and need only be fixed by means of the bolts 29, spacers 28, clamping riders 37, 37' and wing screws 42, 42 in the new subsection II in which concrete is to be placed.

Before the inner formwork skin is caused to follow up by operation of the Winches 32, the method according to the invention calls for intrducing the reinforcement 51 into the space between the formwork skins from the inside. The reinforcement need not be introduced from above, as with known formwork, but may conveniently be brought into position from the inside.

When vthis has been done, the inner formwork skin is,

caused to follow up and concrete is placed in section II. When the concrete has set, the same procedure is repeated with respect to the subsection II in which concrete is to be placed l(FIG. 9b). When the concrete has set also in this section and a subsection -group has thus been completed, the slider is pulled upwardly by one or more subsections, preferably by a subsection group.

Only now is it necessary to adjust the carrying strnctures 23, 24, 25, 26 to the tower dimensions desired in this section of the tower (FIGS. 4 and 9a). It may be necessary to remove some Iof the screw-connected channels, as has been mentioned hereinbefore, if the wedges'haped or triangular gap 34e available at the tightening devices 35, 35 has been used up.

When the adjustment has been effected, the method .is continued as in the rirst subsection 'group (Il, Ill) until the last subsection V has been completed (FIG. 9d). When the slider 15 has reached the top end of the central pole 11, lthe latter is suspended by means of the ropes 18a and the Winches 17a from t-he slider 15,

which is Aanchored in the previously completed part of the towerlike structure. Then the anchoring means at 13 and the locking means 12a are released Iand the Winches 17a are operated to pull the central pole upwardly until it assumes lthe position shown on the left in FIG. 1 relative to the slider.

The method is now continued as has been described hereinbefore.

All parts of the climbing formwork are made from hollow material to reduce the weight as far as possible. The height corresponding to ve height subsections in which concrete is to be placed has also been selected to ensure that the weight of the climbing formworkwill be so light that the formwork may even be used for high and very high structures. The height may obviously be larger or smaller, as may be required.

The formwork skins 30, 31 shown in FIGS. 6 and 7 are straight. This would apply to polygonal structures. In the present case, the formwork skin is actually slightly curved.

The adjustment of the angle of the outer formwork skin relative to the tower axis vmay be eected by means other than the screwed or telescopic connections 24", 25". For instance, the rod 25 may be exactly parallel to the center line 10` whereas the rod 24 is slidably mounted on the connecting tubes 26 for adjustment to the correct angle. It will be apparent that the rod 24 must be clamped fast on the connecting tubes 26 by suitable means after the adjustment has been made.

It will be understood that the method according to the invention could alternatively be carried out by pulling upwardly the inner formwork skin first and the outer formwork skin thereafter. This will be desirable if the working platforms and lifts or elevators for materials are disposed on the outside of the tower on the connecting tubes 26.

Besides, the brackets 41a, 41a (FIG. 6) may extend as far as to the tubes 24 or 23 and be welded there. In that case, the tubes 35a may be omitted. In lthis case, however, the brackets 41a, 41a will have to be formed with recesses on the level of the tightening devices 35, 35 to ensure the passage of the ring tightening rails 38, 38 and the free movement of the wing screws 42, 42.

The wing screws may be replaced by other screws requiring less space. r[he use of Wing screws is recommended, however, because they will enable -an adjustment of the formwork skins without need for tools.

Whereas formwork according to the rst two embodiments is particularly suitable for the erection of towers having a more highly curved generatrix, the formwork described last can be successfully employed for cylindrical or conical structures or tor structures having only a slightly curved generatrix.

It will be understood that the structure of the formwork skins explained with reference to the third embodiment may also be used in the tirst two embodiments.

What is claimed is:

1. A framework for erecting a tower-like concrete structure of circular, oval or cornered cross-section, having a straight or curved generatrix, said formwork being successively elevated in increments as the structure is erected and comprising, in combination:

(a) a vertically extending, hollow central pole .having a plurality of radially extending jib-arms tixedly connected to its upper end and radially extending adjustable arms lxedly connected to its lower end, said ,adjustable arms being securable to the upper part of the previously completed portion of the structure, below said formwork, for supporting the same;

(b) a hollow slider slidably disposed about said pole and having Iradially extending adjustable arms connected to the fformwork skin assembly defined hereinafter;

(c) elevating means carried by said lslider and operatively engaged with the opposite ends of said pole yfor lifting the slider relative to the pole, and for lifting the pole relative to the slider; and

(d) a formwork skin assembly comprising connected inner and outer formwork skins, each of which is supported lby one of said pole and said slider and includes a plurality of skin sections, each of said ski-n sections comprising:

(.1) a plurality of channels disposed one beside the other, adjacent ones of said sections delining gaps bridged by cover plates;

(2) a rst set of adjustable power transmitting members bridging said gaps in said outer formwork skin and adapted to transmit annular tensile stresses between adjacent sections of said outer formwork skin, and

(3) a seco-nd set of adjustable power transmitting members bridging said gaps in said inner formwork skin and adapted to transmit annular compressive stresses between adjacent sections of said inner formwork skin;

each of said power transmitting members comprising a ring tightening rail, two clamping riders displaceably carried by said ring tightening rail, and levers for locking said riders in position on said ring tightening rail.

2. A formwork as set forth in claim 1, in which said cla-mping riders have en d portions oiset a-t right angles.

3. A formwork as set forth i-n claim 2, in which said end portions of the clamping riders of said power transmitting members of said outer formwork skin extend horizontally toward each other to engage said formwork skin sections and prevent an increase of the peripheral extent of the outer formwork skin.

4. A formwork as set forth in claim 2, in which said end portions of the clamping riders of said power transmitting members of said inner formwork skin extend horizontally away from each other to engage said formwork skin sections and prevent a decrease of the peripheral extent of the inner formwork skin.

5. A -fonmwork as set forth in claim 1, in which said ring tightening rail of said inner formwork skin is radially in alignment with a ring tightening rail of said outerv formwork skin and which comprises a plurality of spacers, each of which extends radially between a ring tightening rail of said inner formwork skin and a ring tightening rail of said outer formwork skin in radial alignment therewith, said spacers being formed with tapped bores at opposite ends, said cover plates and ring tightening rails being formed with bores in radial alignment with said tapped bores, and screws bei-ng provided which extend through said bores in said cover plates and ring tighten. ing rails into said tapped bores to determine Ithe spacing of said formwork skins' and to position said cover plates.

(References on following page) 1 1 I 2 lReferences Cited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 10,341 11/1927 Australia. 908,326 12/ 1908 Polk 25-130 368,704 3/1932 Great Britain.

1,127,369 2/1915 Nash. 5

1,457,089 5/ 1923 Sell-man 25-124 ROBERT F. WHITE, Primary Examiner. 1,457,090 5/ 1923 Sellman 25-124 2,414,310 1/1947 La1-d WILLIAM I. STEPHENSON, Examiner.

2,979,798 4/1961 Price 25-130 

1. A FRAMEWORK FOR ERECTING A TOWER-LIKE CONCRETE STRUCTURE OF CIRCULAR, OVAL OR CORNERED CROSS-SECTION, HAVING A STRAIGHT OR CURVED GENERATRIX, SAID FORMWORK BEING SUCCESSIVELY ELEVATED IN INCREMENTS AS THE STRUCTURE IS ERECTED AND COMPRISING, IN COMBINATION: (A) A VERTICALLY EXTENDING, HOLLOW CENTRAL POLE HAVING A PLURALITY OF RADIALLY EXTENDING JIB-ARMS FIXEDLY CONNECTED TO ITS UPPER END AND RADIALLY EXTENDING ADJUSTABLE ARMS FIXEDLY CONNECTED TO ITS LOWER END, SAID ADJUSTABLE ARMS BEING SECURABLE TO THE UPPER PART OF THE PREVIOUSLY COMPLETED PORTION OF THE STRUCTURE, BELOW SAID FORMWORK, FOR SUPPORTING THE SAME, (B) A HOLLOW SLIDER SLIDABLY DISPOSED ABOUT SAID POLE AND HAVING RADIALLY EXTENDING ADJUSTABLE ARMS CONNECTED TO THE FORMWORK SKIN ASSEMBLY DEFINED HEREINAFTER; (C) ELEVATING MEANS CARRIED BY SAID SLIDER AND OPERATIVELY ENGAGED WITH THE OPPOSITE ENDS OF SAID POLE FOR LIFTING THE SLIDER RELATIVE TO THE POLE, AND FOR LIFTING THE POLE RELATIVE TO THE SLIDER; AND (D) A FORMWORK SKIN ASSEMBLY COMPRISING CONNECTED INNER AND OUTER FORMWORK SKINS, EACH OF WHICH IS SUPPORTED BY ONE OF SAID POLE AND SAID SLIDER AND INCLUDES A PLURALITY OF SKIN SECTIONS, EACH OF SAID SKIN SECTION COMPRISING: (1) A PLURALITY OF CHANNESL DISPOSED ONE BESIDE THE OTHER, ADJACENT ONES OF SAID SECTIONS DEFINING GAPS, BRIDGED BY COVER PLATES; (2) A FIRST SET OF ADJUSTABLE POWER TRANSMITTING MEMBERS BRIDGING SAID GAPS IN SAID OUTER FORM- 